JP7383493B2 - Motor control device and motor control method - Google Patents

Description

The present invention relates to a control technology for a direct current (DC) motor, and more particularly to a technology for preventing erroneous pulse generation in a motor control device that generates a pulse (rectangular wave) signal from a current ripple contained in an armature current to control the drive of a motor. .

Conventionally, when controlling the operation of a brushed DC motor, so-called sensorless positioning, which utilizes current ripples that occur when contact between a brush and a commutator piece is switched, has been known as a method for detecting the rotation speed and rotation angle of the brushed DC motor. For example, Patent Document 1 describes a configuration in which the motor rotation speed is detected by detecting a spike-like pulse output generated in the motor current when the brush switches to the next adjacent commutator segment.

On the other hand, the level of the current ripple waveform in a brushed DC motor increases or decreases in proportion to the motor current. However, since the motor current varies greatly depending on the load condition of the motor, the ripple waveform also varies greatly as the load changes. Further, brush noise generated from the motor is also superimposed on the motor current. Therefore, it is not easy to extract only the current ripple from the motor current that includes these unstable elements.

Therefore, as in Patent Document 2, the change in armature current is output as a voltage change signal, the current ripple component and the noise component are extracted from this voltage change signal, and the noise component is removed from there to extract only the current ripple component. A system has also been proposed that generates and outputs a pulse signal from current ripple by extracting it and converting it into a digital signal. With this system, current ripple can be extracted and pulsed using the conventional motor configuration, and ripple sensing can be performed without compromising motor performance or characteristics.

Japanese Patent Application Publication No. 2009-159674 Japanese Patent Application Publication No. 2018-74662

However, even in the method disclosed in Patent Document 2, when the motor is not operating and no current ripple is occurring, static electricity, radio waves, surges, noise from communication equipment, other control equipment, etc. Therefore, if a disturbance with a frequency and voltage similar to the ripple waveform is input to the system, there is a concern that pulses may be output incorrectly. Fig. 3 is a time chart showing the motor operating state and the pulse output (ripple pulse) state. As shown in Fig. 3, when the motor is stopped (X section), ripple pulses are not normally output. However, if noise or the like is input, there is a possibility that an erroneous pulse as shown by the broken line will be generated.

When such an erroneous pulse occurs, a deviation occurs in the pulse count value, and an error occurs in the rotation angle information of the motor, etc., which may impede the operation control of the motor. For example, when a system such as that disclosed in Patent Document 2 is used in a power window motor, a discrepancy in the pulse count may lead to false detection of the window position, the window operating speed may deviate from the expected one, or the recognition of the mask area for entrapment detection may be affected. There was a risk that misalignment would occur.

An object of the present invention is to prevent the generation of erroneous pulses caused by noise or the like when the motor is de-energized or stopped in a motor control device that generates pulse signals from current ripples to control the drive of a motor.

The motor control device of the present invention includes a ripple pulse converter that detects current ripple included in the armature current of the DC motor and outputs the current ripple as a pulse signal , and a ripple pulse converter that detects the current ripple from the armature current of the DC motor. a detection sensitivity adjustment section for adjusting the sensitivity of the ripple detection sensitivity adjustment section; The present invention is characterized in that the detection sensitivity of the current ripple is reduced .

In the present invention, the ripple detection sensitivity adjustment section lowers the current ripple detection sensitivity when the motor is in a non-energized/stopped state. This makes it possible to suppress the generation of erroneous pulses even if disturbances such as noise occur during the non-energized/stopped period when no pulse signal is supposed to be generated. Therefore, even when controlling a motor based on pulse counts, for example, it is possible to prevent deviations in count values, suppress errors in motor rotation angle information, and improve motor control accuracy. Become.

In the motor control device, the ripple detection sensitivity adjustment section includes a motor voltage input determination section that determines the energization state of the DC motor based on the terminal voltage of the DC motor, and a motor voltage input determination section that determines the energization state of the DC motor based on the terminal voltage of the DC motor; a ripple pulse input determination section that determines the operating state of the DC motor based on a pulse signal; and a ripple pulse input determination section that determines the operating state of the DC motor, and a ripple pulse input determination section that determines whether the DC motor is in a de-energized state and An amplification degree adjustment section may be provided that reduces the amplification degree in the ripple pulse conversion section and decreases the detection sensitivity of the current ripple when it is determined that the current ripple is in a stopped state.

In this case, the motor voltage input determination unit may detect voltages before and after the DC motor, and determine whether or not the DC motor is energized based on the voltage values of both. Further, the ripple pulse input determination section includes a ripple pulse detection section that separates the pulse signal into a DC component and a pulse signal, and a ripple pulse smoothing section that converts the pulse signal separated by the ripple pulse detection section into a DC component. and a differential amplifier section that outputs a signal when the voltage value of the pulse signal converted into a DC component by the ripple pulse smoothing section exceeds a predetermined reference voltage.

On the other hand, the motor control method of the present invention is a motor control method that detects a current ripple included in an armature current of a DC motor and controls the operation of the DC motor based on a pulse signal generated from the current ripple. , the detection sensitivity of the current ripple is reduced when the DC motor is not energized and is not operating.

In the present invention, when the motor is in a non-energized/stopped state, the current ripple detection sensitivity is reduced. This makes it possible to suppress the generation of erroneous pulses even if disturbances such as noise occur during the non-energized/stopped period when no pulse signal is supposed to be generated. Therefore, even when controlling a motor based on pulse counts, for example, it is possible to prevent deviations in count values, suppress errors in motor rotation angle information, and improve motor control accuracy. Become.

According to the motor control device of the present invention, in the motor control device including the ripple pulse conversion section that generates a pulse signal from the current ripple included in the armature current of the DC motor, the DC motor is not energized, and Since a ripple detection sensitivity adjustment section is provided that lowers the current ripple detection sensitivity when the device is not in operation, it is possible to suppress the generation of erroneous pulses even if disturbances such as noise occur when the device is not energized or stopped. Therefore, even when controlling a motor based on pulse counts, for example, it is possible to prevent deviations in count values, suppress errors in motor rotation angle information, and improve motor control accuracy. Become.

According to the motor control method of the present invention, in the motor control method for controlling the operation of the DC motor based on a pulse signal generated from a current ripple included in the armature current of the DC motor, the DC motor is not energized. In addition, since the current ripple detection sensitivity is lowered when the device is not in operation, it is possible to suppress the generation of erroneous pulses even if disturbances such as noise occur when the device is not energized or stopped. Therefore, even when controlling a motor based on pulse counts, for example, it is possible to prevent deviations in count values, suppress errors in motor rotation angle information, and improve motor control accuracy. Become.

1 is a block diagram showing the configuration of a motor control device that is an embodiment of the present invention. 2 is a truth table in a ripple detection sensitivity adjustment section provided in the motor control device of FIG. 1. FIG. FIG. 3 is an explanatory diagram showing the relationship between motor operation and ripple pulses.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a block diagram showing the configuration of a motor control device 1 according to an embodiment of the present invention, and the motor control device 1 is applied, for example, to control the operation of a motor for a power window of a vehicle. The motor control device 1 is provided with a ripple pulse converter 10 that extracts the current ripple contained in the motor current (armature current) without using a Hall IC or the like and outputs it in the form of a pulse signal.

The ripple pulse converter 10 is arranged on a power supply line 4 that supplies power from a motor driver (power supply) 2 to a brushed DC motor 3 (hereinafter abbreviated as motor 3). A shunt resistor 5 is provided in the power supply line 4, and the ripple pulse converter 10 is connected before and after the shunt resistor 5 (on the motor driver 2 side and the motor 3 side). The motor control device 1 calculates the rotation speed, rotation direction, etc. of the motor 3 based on the pulse output (ripple pulse) from the ripple pulse converter 10, and controls the operation of the motor 3.

The ripple pulse conversion section 10 is provided with a current detection section 11 , a first smoothing circuit 12 , a gain adjustment section 13 , a second smoothing circuit 14 , a ripple detection section 15 , and a digital signal conversion section 16 . The current detection unit 11 detects the voltage difference (voltage drop) across the shunt resistor 5 to detect the motor drive current, and outputs the change as a voltage change signal. This voltage change signal is sent from the first smoothing circuit 12 to the gain adjustment unit 13 → second smoothing circuit 14 → ripple detection unit 15, noise components are removed from the voltage change signal, and only the current ripple component is extracted. The extracted current ripple component is converted into a pulse signal equivalent to an encoder output by the digital signal converter 16, and a ripple pulse is generated and output.

In the pulse signal generated by the ripple pulse converter 10, each pulse corresponds to a change in contact between the brush and the commutator bar. Since the number of brushes and commutator pieces is predetermined for each motor, the number of rotations of the motor 3 can be calculated by counting these pulses. That is, the rotation speed of the motor 3 is detected from the current ripple in the motor current without using a rotation detection member such as a Hall IC. At this time, the ripple pulse converter 10 can extract ripples from the motor current using the conventional motor configuration.

On the other hand, the motor control device 1 according to the present invention is further provided with a ripple detection sensitivity adjustment section 21 that adjusts the sensitivity for detecting current ripple from the motor current. The ripple detection sensitivity adjustment section 21 includes a motor voltage input determination section 22, a ripple pulse input determination section 23, and an amplification degree adjustment section 24, and when the motor 3 is not energized and is not operating, The degree of amplification in the ripple pulse converter 10 is lowered to lower the current ripple detection sensitivity.

As shown in FIG. 1, the motor voltage input determination unit 22 detects the voltages VA and VB (motor terminal voltages) before and after the motor 3, and determines the energization state of the motor 3 (whether or not it is energized) based on the voltage values of both. ) is determined. The ripple pulse input determination unit 23 determines the operating state of the motor 3 (whether it is rotating or stopped) based on the presence or absence of ripple pulses. The amplification degree adjustment section 24 adjusts the amplification degree in the gain adjustment section 13 (gain control) based on the outputs from the motor voltage input determination section 22 and the ripple pulse input determination section 23, and adjusts the current ripple detection sensitivity.

In this case, the ripple pulse input determination section 23 includes a ripple pulse detection section 25 that separates the ripple pulse output from the ripple pulse conversion section 10 into a DC component (direct current component) and a pulse signal; The ripple pulse smoothing unit 26 converts the pulse signal into a DC component, and the voltage value of the pulse signal converted into a DC component by the ripple pulse smoothing unit exceeds a predetermined reference voltage (Bias voltage: Voff). It also includes a differential amplification section 27 that outputs a signal when the signal is output.

Furthermore, when the motor 3 is in a non-energized state and ripple pulses are not generated continuously, the amplification degree adjustment section 24 considers that the motor 3 is in a stopped state, and lowers the amplification degree of the ripple pulse conversion section 10. function and reduce ripple detection sensitivity. As a result, even if there is a disturbance input, the ripple pulse converter 10 does not generate a corresponding pulse, and the generation of erroneous pulses due to the disturbance is suppressed. FIG. 2 is a truth table in the ripple detection sensitivity adjustment section 21, and the ripple detection sensitivity adjustment section 21 adjusts the gain of the ripple pulse conversion section 10 by the following processing.

(1) When the motor is energized and rotates steadily When the motor 3 is energized and rotates steadily, either the terminal voltage VA or VB of the motor 3 becomes "H (Hi)". Here, the settings are "VA:H, VB:L (Low)" for CW rotation, and "VA:L, VB:H" for CCW rotation. Therefore, in the case of energization and steady rotation, the output D (output of NAND 33) after passing through NOT31 and 32 becomes "H" in both CW rotation and CCW rotation. That is, when the motor 3 is energized, the output from the motor voltage input determining section 22 becomes "H".

On the other hand, a ripple pulse (hereinafter abbreviated as RP) is input to the ripple pulse input determination section 23 from the ripple pulse conversion section 10. In the ripple pulse input determination section 23, since the RP output may be fixed at "H" when RP is not generated, first, the ripple pulse is converted into a DC component and a pulse signal in the ripple pulse detection section 25 using a differentiating circuit. Separate. Next, the pulse signal obtained by the ripple pulse detection section 25 is converted into a DC component by the ripple pulse smoothing section 26. The output A of the ripple pulse smoothing section 26 is input to the differential amplification section 27, and an output B is generated based on the relationship with a predetermined Bias voltage (Voff).

In this case, the Bias voltage is set so that the output A>Voff when tens of pulses or more (for example, 20 pulses or more) are continuously generated in order to distinguish between disturbance and normal operation. Therefore, during energization and steady rotation, RP is output continuously over several tens of pulses, so the output A of the ripple pulse smoothing section 26 becomes larger than the Bias voltage, and the output B of the differential amplifier section 27 becomes "H". ”.

The amplification degree adjustment unit 24 receives the output D: “H” from the motor voltage input determination unit 22 and the output B: “H” from the differential amplifier unit 27, and inputs E and C of the NAND 34 are inputted by NOTs 35 and 36. They are "L" and "L" respectively. Therefore, the output F of the NAND34 becomes "H" and the output G of the NOT37 becomes "L". As a result, the gate of the transistor (switching element) 38 becomes "L", and the collector side P of the transistor 38 becomes open. As a result, no gain control is performed on the gain adjustment section 13, ripple pulse detection is performed at a normal amplification degree, and drive control of the motor 3 is performed.

(2) When the motor is not energized and is coasting When the motor 3 is not energized but is coasting, strictly speaking, an induced voltage is generated in the motor 3, and the monitored terminal Either voltage VA or VB becomes "H". However, the induced voltage at that time is very small compared to when the motor is energized and rotates steadily. Therefore, in the ripple detection sensitivity adjustment section 21, when VA and VB are less than a predetermined voltage, they are set to "L". As a result, "H" and "H" are input to NAND33 via NOT31 and 32, and in the case of non-energization and coasting rotation, the output D becomes "L" in both CW rotation and CCW rotation. Become.

On the other hand, during coasting rotation, RP of several dozen or more continuous pulses is input to the ripple pulse input determination unit 23, unlike when the engine is stopped. Therefore, in the case of non-energized/coasting rotation, the output A becomes larger than the Bias voltage, and the output B of the differential amplifier section 27 becomes "H". The amplification degree adjustment unit 24 receives the output D: “L” from the motor voltage input determination unit 22 and the output B: “H” from the differential amplifier unit 27, and the inputs E and C of the NAND 34 are They become "H" and "L" respectively. Therefore, the output F of the NAND 34 becomes "H", the output G of the NOT 37 becomes "L", and the collector side P of the transistor 38 becomes open. As a result, the gain control for the gain adjustment section 13 is not performed, and the drive control (ripple pulse detection) of the motor 3 is performed at the normal amplification degree.

(3) When the motor is de-energized and reversed When the motor 3 is restricted from rotating during steady rotation, and then the power is turned off, the motor 3 may reverse due to the reaction of the motor mechanism. In this case, either the terminal voltage VA or VB becomes "H", but as in the case of de-energization and coasting, the induced voltage at that time is minute compared to that during steady rotation, so adjust the ripple detection sensitivity. In the section 21, VA and VB are handled as "L". As a result, "H" and "H" are input to the NAND 33 via the NOTs 31 and 32, and the output D becomes "L" in both CW rotation and CCW rotation, even in the case of non-energization and reverse rotation.

In addition, even during reverse rotation, the ripple pulse input determination section 23 receives RP of several dozen or more continuous pulses to some extent, so the output B of the differential amplifier section 27 is It becomes "H". Then, the output D: "L" from the motor voltage input determination section 22 and the output B: "H" from the differential amplification section 27 are input to the amplification degree adjustment section 24, as in the case of de-energized/coasting. , the inputs E and C of the NAND34 become "H" and "L" due to the NOTs 35 and 36, respectively. Therefore, the output F of the NAND 34 is "H", the output G of the NOT 37 is "L", the collector side P of the transistor 38 is open, and no gain control is performed on the gain adjustment section 13.

(4) When the motor is de-energized/stopped When the motor 3 is stopped without being energized, VA and VB become "L". As a result, "H" and "H" are input to the NAND 33 via the NOTs 31 and 32, and in the case of de-energization/stop, the output D becomes "L". Furthermore, when stopped, consecutive RPs are not input to the ripple pulse input determining section 23. Therefore, in the case of stopping, the output A becomes smaller than the Bias voltage, and the output B of the differential amplifier section 27 becomes "L".

At this time, the output D: "L" from the motor voltage input determination section 22 and the output B: "L" from the differential amplifier section 27 are input to the amplification degree adjustment section 24, and the inputs E and C of the NAND 34 are input to the NOT 35. , 36 become "H" and "H", respectively. Therefore, the output F of the NAND34 becomes "L" and the output G of the NOT37 becomes "H". Then, at this time, the gate of the transistor 38 becomes "H", and the collector side P of the transistor 38 is electrically connected to the emitter side and grounded, and becomes "L". As a result, the gain control voltage of the gain adjustment section 13 becomes "L", and the degree of amplification is lowered. As a result, the sensitivity of the ripple pulse converter 10 is lowered, and even if noise or the like is input to the section X in FIG. 3 (when the motor is stopped), it is possible to suppress the generation of erroneous pulses as shown by the broken line.

As described above, in the motor control device 1 of the present invention, when the motor 3 is in a non-energized/stopped state, the ripple pulse converter 10, which extracts the current ripple contained in the motor current and outputs a ripple pulse, converts the current ripple into the ripple pulse converter 10. By providing the ripple detection sensitivity adjustment section 21 that lowers the detection sensitivity, it is possible to suppress the generation of erroneous pulses even if disturbances such as noise occur during the period when no ripple pulses are generated. Therefore, even when controlling a motor based on pulse counts, for example, it is possible to prevent deviations in count values, suppress errors in motor rotation angle information, and improve motor control accuracy. Become. Therefore, by using the control device for the power window motor as in this embodiment, it is possible to prevent false detection of the window position due to pulse count deviation. As a result, the control accuracy of the power window is improved, and the control accuracy of window operation speed and pinch detection is also improved.

It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the gist thereof.
For example, the functions of the above-mentioned motor control device can be replaced and realized by software rather than by hardware configurations such as the ripple pulse converter 10 and the ripple detection sensitivity adjuster 21. be.

The motor control device according to the present invention not only controls the operation of a power window motor, but also controls pulses from motor drive current for other in-vehicle electric devices such as wipers and power seats, and household electrical appliances using brushed motors. It is widely applicable to devices using detection technology.

1 Motor control device 2 Motor driver 3 Brushed DC motor 4 Power line 5 Shunt resistor 10 Ripple pulse conversion section 11 Current detection section 12 First smoothing circuit 13 Gain adjustment section 14 Second smoothing circuit 15 Ripple detection section 16 Digital signal conversion section 21 Ripple detection sensitivity adjustment section 22 Motor voltage input judgment section 23 Ripple pulse input judgment section 24 Amplification degree adjustment section 25 Ripple pulse detection section 26 Ripple pulse smoothing section 27 Differential amplification section 31 NOT
32 NOT
33 NAND
34 NAND
35 NOT
36 NOT
37 NOT
38 Transistor

Claims (5)

a ripple pulse converter that detects a current ripple included in the armature current of the DC motor and outputs the current ripple as a pulse signal ;
A motor control device comprising: a ripple detection sensitivity adjustment section that adjusts sensitivity for detecting current ripple from the armature current of the DC motor ,
The motor control device is characterized in that the ripple detection sensitivity adjustment unit lowers the detection sensitivity of the current ripple when the DC motor is not energized and is not operating. The motor control device according to claim 1,
The ripple detection sensitivity adjustment section is
a motor voltage input determination unit that determines an energization state of the DC motor based on a terminal voltage of the DC motor;
a ripple pulse input determination unit that determines the operating state of the DC motor based on the pulse signal output from the ripple pulse conversion unit;
If it is determined that the DC motor is in a de-energized state and in a stopped state based on the determination results of the motor voltage input determination section and the ripple pulse input determination section, the amplification degree in the ripple pulse conversion section is lowered, and the A motor control device comprising: an amplification degree adjustment section that reduces current ripple detection sensitivity. The motor control device according to claim 2,
The motor control device is characterized in that the motor voltage input determination unit detects voltages before and after the DC motor, and determines whether or not the DC motor is energized based on the voltage values of both. The motor control device according to claim 2,
The ripple pulse input determination section includes:
a ripple pulse detection unit that separates the pulse signal into a DC component and a pulse signal;
a ripple pulse smoothing unit that converts the pulse signal separated by the ripple pulse detection unit into a DC component;
A motor control device comprising: a differential amplifier unit that outputs a signal when the voltage value of the pulse signal converted into a DC component by the ripple pulse smoothing unit exceeds a predetermined reference voltage. . A motor control method that detects a current ripple included in an armature current of a DC motor and controls the operation of the DC motor based on a pulse signal generated from the current ripple, the method comprising:
A motor control method characterized in that the detection sensitivity of the current ripple is reduced when the DC motor is not energized and is not operating.

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